billiard() creates a surface from a polygon. It is essentially equivalent to polygon_double(). However, their plotting used to be different.
billiard() used to plot trajectories in a single polygon (internally using one positively and one negatively oriented copy of the polygon) whereas polygon_double() drew trajectories in two positively oriented copies of the polygon.
We should restore this feature somehow. Probably we should get rid of special plotting logic but instead have a map from the polygon_double() to the surface (with boundary) formed by the single polygon. We can then plot such trajectories by plotting their image under this map.
billiard()creates a surface from a polygon. It is essentially equivalent topolygon_double(). However, their plotting used to be different.billiard()used to plot trajectories in a single polygon (internally using one positively and one negatively oriented copy of the polygon) whereaspolygon_double()drew trajectories in two positively oriented copies of the polygon.We should restore this feature somehow. Probably we should get rid of special plotting logic but instead have a map from the
polygon_double()to the surface (with boundary) formed by the single polygon. We can then plot such trajectories by plotting their image under this map.